(1) Field of the Invention
This invention relates to a method for sterilizing a cosmetic product, in which said product consists of a fluid circulating under pressure within a sterilization circuit, the method consisting in successively preheating said product; briefly heating said product at high temperature; immediately cooling said product; and packaging the product in a sterile atmosphere.
This invention falls within the field of cosmetology, in particular the manufacture of cosmetic products.
The invention relates more specifically to a method for sterilizing cosmetic products and a device for its implementation.
(2) Description of the Prior Art
In order to improve the preservation of a cosmetic product, in its composition are included preservatives having in particular the function of preserving the properties of said product, yet protecting it against contamination. The preservatives are classified in a list identified by authorized organizations. One group of preservatives used are parabens that prevent the growth of fungi and bacteria. However, these components have the disadvantage of being harmful to the body and are a hazard for users' health.
Producers therefore try to substitute parabens by other compounds that can be used as preservatives. However, the products used are not always present in the authorized lists and they do not provide full satisfaction.
Therefore, it was thought to sterilize the cosmetic products instead of incorporating preservatives. Several methods and devices of the state of the art, described for example in JP 60025907 and JP 10025235, consist in sterilizing, by heating, the cosmetic product in a temperature range between 50 and 80 degrees Celsius. However, the devices do not provide full satisfaction as to the longevity of the product and are complex to be implemented.
Therefore, it has been thought of sterilizing at very high temperature, in the range of 135° to 150°, still by means of circulating a fluid through a circuit traversing heating and cooling baths. Such a device is described in US 2002/164159, for sterilizing several types of products, as cosmetics, but the application of which is designed in particular for milk sterilization.
This device has disadvantages in that it is designed for the sterilization of one single product. As a matter of fact, the sterilization time in this case is adapted by increasing or diminishing the length of the circuit. Therefore, the same plant can only be dedicated to one single product, having a certain viscosity. Furthermore, the sterilization time is very long, in the range of 80 minutes, by means of circulation within a Joule-effect tubular exchanger. The high temperatures combined with this long time require high speed of product circulation, in the range of 5 meters per second.
Other solutions have been contemplated, for example in U.S. Pat. No. 5,976,592, having recourse to an electromagnetic field in order to irradiate the product and thus heat it, then cool it in a water and glycol bath at approximately 15 degrees Celsius. Such a device does not provide full satisfaction, in particular because of the complexity and of the production and utilization cost. Furthermore, one installation is dedicated to the sterilization of one and the same product having a certain viscosity.